It is well-known that jewelry and certain other items are particularly attractive in appearance when they are brilliantly lit while on display, e.g. in a display case. Heretofore, arranging for lighting of such display cases has been a problem; high intentisy incandescent lighting produced much unwanted heat which in some instances required forced ventilation of display cases and in others caused premature deterioration of interior components and display materials such as glue, paper, fabric and the like, due to the hot, dry conditions within the display case. Evenness of lighting has been a problem; even with the use of diffusers and reflectors, certain regions of the display area within typical cases were apparently more brightly lit. In some instances, the cost of electricity for powering the lighting and the cost of replacing spent bulbs has been considered excessive. Conventional fluorescent lighting heretofore available has not proved to be an adequate solution of the problems; though they generate less heat, usually the level of illumination they provide does not permit brilliant lighting e.g. for jewelry displays and the like, and sometimes the hue of the standard fluorescent lighting is not so complementary to the merchandise.
Recently, several lamp manufacturers have come out with compact fluorescent lamps which differ from heretofore conventional straight line fluorescent tubes having a base at each end, in that on these new lamps, the tube is folded-over mid-way along its length, so that both ends share the same lamp base in common, much as do conventional incandescent light bulbs.
Such compact fluorescent lamps are available in the U.S., e.g. from North American Philips Lighting Corporation, of Bloomfield, N.J. under the "Norelco" brand name as "PL" lamps in 7-, 9-and 13-watt sizes. Lampholders are available in the U.S. for such lamps, e.g. from Leviton Manufacturing Co., Inc., of Little Neck, N.Y., e.g. as its series 26720 for the 13-watt lamps, catalog No. 26720-2 being its horizontal screw or slide-on mount lamp holder for the 13-watt lamps. Lamp ballasts for such lamps and lamp holders, not requiring starters, have become available in the U.S., e.g. from Radonic Industries, Inc. of Chicago, Ill., catalog No. C452 being its designation for a ballast, having a Q-style case, for serving such a lamp and lamp holder.
Similar lamps are available in the U.S., from the manufacturer of "Sylvania" brand light bulbs, under the designation Compact TT twin tube fluorescents.
For the Norelco lamps, lamp holders (sockets) are also available from Kulka Wiring Devices, Inc., of Mt. Vernon, N.Y. and Edwin Gaynor Company, of Stratford, Conn.; and lamp ballasts are also available from Advance Transformer Company, of Chicago, Ill., Robertson Transformer Company, of Blue Island, Ill., Universal Manufacturing Corporation, of Paramus, N.J., and Keystone Transformer Company, of Pennsburg, Pa.
The new form of lighting, herein designated single base compact fluorescent lamp lighting is said by the lamp manufacturer to combine in one lamp: high efficiency (up to 69.2 lumens per watt, so that a 13-watt lamp provides up to 900 lumens and can replace a 60-75-watt conventional lighting source at an up to 77 percent energy cost saving); a color temperature of 2700.degree. K. (that is similar to the 2750.degree. K. color temperature of a standard incandescent lamp so that it reflects color in a `warm` way that is more characteristic of natural sunlight and of incandescent lighting, than of conventional fluorescent lighting); long life (about ten-times that of the 1000-hour average for a conventional incandescent bulb of comparable illumination level); low radio interference; ability to start at low temperature; and a differentiation in base/socket design for the 13-watt size compared with the smaller wattage lamps, so one may by providing a particular socket ensure that lamps of a particular wattage are used. The manufacturers of these lamps have recognized that cabinet fixtures can be reduced in size and less materials used in manufacture when single base compact fluorescent lamps are used for their display space lighting. However, heretofore, to the present inventors' knowledge, display case designers have not taken anywhere near full advantage of this new case-lighting possibility, either for new cases or for retrofitting of existing cases.